Biblio

In this paper, we present a study about the remanence state and coercivity in 1-D chain of cobalt hollow nanospheres, by using micromagnetic simulation. The high coercivity values (Hc is determined in the range of 600-1800 Oe) and the monotonic decrease of remanence are attributed to the shape anisotropy effect due to an increase in the aspect ratio value. The configuration of magnetization in remanence showed the onion state for hollow spheres (HSs) with Re = 15 nm, whereas for Re = 30 nm, appear the curling-vortex (CV) state. Finally for a cluster of chains, constituted by cobalt HSs, with random orientations the CV state is preserved.

Macroscopic hysteresis loops and microscopic magnetic moment distributions have been determined by 3-D model for Co nanowire with various easy axis deviations from applied field. It is found that both the coercivity and the remanence decrease monotonously with the increase of easy axis deviation as well as the maximum magnetic product, indicating the large impact of the easy axis orientation on the magnetic performance. Moreover, the calculated angular distributions and the evolution of magnetic moments have been shown to explain the magnetic reversal process. It is demonstrated that the large demagnetization field in the two ends of the nanowire makes the occurrence of reversal domain nucleation easier, hence the magnetic reversal. In addition, the magnetic reversal was illustrated in terms of the analysis of the energy evolution.

In last decades' web application security has become one of the most important case study of information security studies. Business processes are transferred to web platforms. So web application usage is increased very fast. Web-based attacks have also increased due to the increased use of web applications. In order to ensure the security of web applications, intrusion detection and prevention systems and web application firewalls are used against web based attacks. Blockchain technology, which has become popular in recent years, enables reliable and transparent sharing of data with all stakeholders. In this study, in order to detect web-based attacks, a blockchain based web attack detection model that uses the signature based detection method is proposed. The signature based detection refers to the detection of attacks by looking for specific patterns against known web based attack types, such as Structured Query Language (SQL) Injection, Cross Site Scripting (XSS), Command Injection. Three web servers were used for the experimental study. A blockchain node has been installed with the MultiChain application for each server. Attacks on web applications are detected using the signature list found in the web application as well as detected using the signature list updated on the blockchain. According to the experimental results, the attacks signature detected and defined by a web application are updated in the blockchain lists and used by all web applications.

This paper presents a new class of high-performance permanent micro-magnets based on the controlled assembly of cobalt nanorods for the electromagnetic transduction of MEMS. Micromagnets are fabricated using a low temperature fabrication process that yields a dense material exhibiting high coercive field and remanence to saturation magnetization ratio. The cartography of the magnetic induction produced by the sub-millimeter size magnets was obtained using a scanning Hall effect micro-probe microscope. Silicon microcantilevers placed in the vicinity of these magnets were successfully actuated using the Lorentz force with low currents. The good signal to noise ratio measured at resonance demonstrates the potentiality of these nanostructured micro-magnets.